TWI436165B - Photoimageable branched polymer - Google Patents

Description

Photoimageable branched polymer [Reciprocal Reference of Related Applications]

The present application claims the benefit of U.S. Provisional Application Serial No. 60/983,778, the entire disclosure of which is incorporated herein by reference.

The present disclosure relates to novel photoimageable branched polymers, including developer-soluble photosensitive anti-reflective coating compositions of the polymers, and methods of using the same.

As feature sizes shrink to 65 nanometers or less, new and more advanced materials will be needed to meet the goals set by the semiconductor industry. The photoresist used in the imaging procedure, the bottom anti-reflective coating and any other layers must work together to achieve a high resolution etch target. For example, because the new photoresist is much thinner than the older generation of materials, the loss of photoresist thickness that occurs during the bottom anti-reflective coating and substrate etching steps becomes a serious problem. Although the photoresist thickness is reduced, it is not expected that the thickness of the bottom anti-reflective coating will decrease at the same rate, which makes the problem of photoresist wear more complicated. One way to solve this problem is to eliminate the bottom anti-reflective coating etch step by using a wet developable or developer soluble bottom anti-reflective coating or other wet developable underlayer. The wet developable layer has typically used polyamic acid which is soluble in an alkaline medium as a polymer binder, whereby the film is removed upon development of the photoresist. These conventional wettable development materials are insoluble in the photoresist solvent by the use of thermally driven imiline-quinone imine. This method proceeds smoothly, but it has two limitations: 1) when the film is insoluble in organic solvents but soluble in alkaline developer, the baking temperature range may be narrow (less than 10 ° C); and 2) wet development The procedure is isotropic, meaning that the vertical and horizontal removal rates of the film are the same, resulting in an undercut of the photoresist line. While this is not a problem for larger geometries (greater than 0.2 microns), it tends to cause the float and line to collapse for smaller wire sizes.

Summary of invention

The present invention is generally directed to methods of forming microelectronic structures. In the method, a substrate having a surface is provided, and a composition is applied to the surface. The composition includes a compound comprising a branched polymer, a branched oligomer, or a mixture thereof, the compound having a first molecular weight.

The compound in the composition is crosslinked, followed by exposing the composition to light and baking to deblock the compound and break the compound into portions. At least about 80% of the individual molecular weight of the resulting portion is less than the first molecular weight of the compound.

Detailed description of preferred embodiments

The present invention solves the problem of the isotropic development of the developer soluble coating of the prior art by using a crosslinking/decrosslinking/depolymerizing mechanism which makes the film only soluble in alkali in the exposed region. In this way, horizontal development (undercut) is minimized or eliminated. In addition, after exposure, the presence of small molecules that replace giant molecules improves imaging performance because small molecules are more easily removed and more soluble than macromolecules.

Broadly speaking, the composition comprises a group selected from the group consisting of branched polymers, branched oligomers, or mixtures thereof dissolved or dispersed in a solvent system.

Preparation of branched polymers or oligomers

Compounds (i.e., branched or non-linear polymers or oligomers) can be formed by reacting a polyfunctional acid with a polyfunctional vinyl ether to form a hemiacetal ester or acetal structure. Regarding the polyfunctional acid, any acidic group which can react with the vinyl ether is suitable. More particularly, an acidic group having a pKa of 4 to 11 is acceptable. Preferred such acidic groups include those selected from the group consisting of carboxylic acids, phenols, sulfonamides, fluorinated alcohols, and mixtures thereof. Examples of suitable fluorinated alcohols include those selected from the group consisting of

The acidic group can be present on the oligomer, polymer or compound. For example, acidic groups can be present on the substituted and unsubstituted acrylates, methacrylates, novolacs, isocyanurates, glycidyl ethers, and mixtures thereof.

The amount of the acid group present on the polyfunctional acid oligomer or compound is preferably at least about 23% by weight, more preferably from about 29% to about, based on 100% by weight of the polyfunctional acid oligomer or the total weight of the compound. 79% by weight, and still more preferably from about 39% to about 78% by weight.

Preferred polyfunctional vinyl ethers are di-, tri- and/or tetra-functional and have the formula

R'-(XO-CH=CH ₂ ) _n ,

Wherein R' is selected from the group consisting of an aryl group (preferably C ₆ -C ₁₄ ) and an alkyl group (preferably C ₁ -C ₁₈ , and more preferably C ₁ -C ₁₀ ), each X being independently selected from An alkyl group (preferably C ₁ - C ₁₈ , and more preferably C ₁ - C ₁₀ ), an alkoxy group (preferably C ₁ - C ₁₈ , and more preferably C ₁ - C ₁₀ ), a carbonyl group, and the aforementioned two or more A group consisting of multiple combinations, and n is 2-6. The most preferred vinyl ethers include those selected from the group consisting of ethylene glycol vinyl ether, trimethylolpropane trivinyl ether, 1,4-cyclohexane dimethanol divinyl ether, and mixtures thereof. Another preferred vinyl ether has a formula selected from the group consisting of

The polyfunctional acid and the polyfunctional vinyl ether are preferably reacted in the presence of an acid catalyst. Preferred acid catalysts are selected from the group consisting of p-toluenesulfonic acid pyridine ("PPTS"), sulfonate salicylic acid pyridine, p-toluenesulfonic acid ("pTSA") other thermal acid generators (TAG). The acid catalyst is preferably used in an amount of from about 0.15% to about 0.60% by weight, more preferably from about 0.19% to about 0.4% by weight, based on the total weight of the reaction solution as 100% by weight.

The polyfunctional acid ("MFA") and the polyfunctional vinyl ether ("MFVF") are preferably reacted at an MFA:MFVF equivalent ratio of from about 1:1.3 to about 1:0.7, and more preferably from about 1:1.1 to about 1:0.9. . Further, the reaction preferably comprises a solvent selected from the group consisting of propylene glycol acetate ("PGMEA"), propylene glycol methyl ether ("PGME"), propylene glycol n-propyl ether ("PnP"), ethyl lactate, propylene glycol n-butyl ether ("PnB" The process is carried out in a solvent system of a solvent consisting of cyclohexanol, tetrahydrofuran ("THF"), diethyl ether, dichloromethane, chloroform, γ-butyrolactone, and mixtures thereof. The boiling point of the solvent system is preferably from about 50 ° C to about 250 ° C, and more preferably from about 100 ° C to about 175 ° C. The solvent system should be used in an amount of from about 65% to about 99% by weight, and preferably from about 69% to about 98% by weight, based on the total weight of the reaction formulation as 100% by weight. The reaction is preferably carried out for a period of time of from about 14 hours to about 36 hours, preferably at ambient temperature and while stirring.

Preferably, at the end of the reaction time, a quencher is added to neutralize any residual acid and any acid that may be thermally generated during the reaction. When used, the amount of the quenching agent added is substantially from about 0.75% to about 1.30% by weight, and more preferably from about 0.80% to about 0.85% by weight, based on the total weight of the reaction solution as 100% by weight. Suitable quenchers include those selected from the group consisting of triethanolamine ("TEA"), pyridine, and mixtures thereof.

During the preparation procedure, several acid groups will react with the vinyl ether group to form an initial number of hemiacetal or acetal linkages of the formula

Wherein R is selected from the group consisting of aryl (preferably from about C ₆ to about C ₁₄ ), alkyl (preferably from about C ₁ to about C ₈ ), and aralkyl (from about C ₆ to about C ₁₂ and about C, respectively). ₁ to about C _{8 is} preferred), alkenyl (preferably from about C ₁ to about C ₈ ), cyclic group (preferably from about C ₅ to about C ₁₀ ), -CO-, -SO-, -S- , a group consisting of -CONH-, diol and adamantyl.

A particularly preferred R group is selected from the group consisting of the following formula

However, not all acid groups react with vinyl groups. The acid group which is not reacted with the polyfunctional vinyl ether is preferably present in the branched compound in an amount of at least about 2% by weight, preferably from about 4% to about 60% by weight, based on the total weight of the compound as 100% by weight. More preferably from about 20% to about 55% by weight. Further, based on the total weight of the compound as 100% by weight, the vinyl group which is not reacted with the acid group will be present in an amount of at least about 2% by weight, preferably from about 4% to about 60% by weight, and about 20% by weight. More preferably to about 55% by weight.

In a specific example, the branched polymer or oligomer can be represented by the following formula

Wherein: each R _{3 is} individually selected from the group consisting of an alkyl group (preferably C ₁ -C ₈ ), an aryl group (preferably from about C ₆ to about C ₁₄ ), and a functional derivative thereof; Free group

Each x, y, and z is individually selected from the group consisting of 0 and 1; and at least one of x, y, and z is 1.

Unlike the compositions of the prior art, unreacted acid groups are preferably protected by unprotected groups. That is, at least about 95%, preferably at least about 98%, and more preferably about 100% of the acid groups which are not reacted with the polyfunctional vinyl ether have no protecting groups. The protecting group prevents the acid from being reactive.

Preparation of coating compositions comprising branched polymers and/or oligomers

The aforementioned mother liquor can be used to prepare a coating composition. Alternatively, polymers conforming to the foregoing specifications are commercially available and used to make coating formulations.

In either manner, the coating composition will be prepared by mixing additional ingredients with a mother liquor comprising the branched compound. The component to be included in the coating composition is a catalyst. Preferred catalysts are acid generators, especially photoacid generators ("PAG", both ionic and/or nonionic). Any PAG that produces acid in the presence of light is suitable. Preferred PAGs include phosphonium salts (e.g., tris(triphenylperfluorosulfonate) such as triphenylnonafluorofluoride methanesulfonate and triphenylsulfonium triflate), sulfonium-sulfonates (e.g., CIBA) By name Seller) and three (for example, available from Midori Kagaku Company ).

The coating composition preferably comprises from about 0.35% to about 10% by weight of a catalyst (preferably PAG) based on the total weight of the polymer and oligomer solids in the composition as 100% by weight, and comprises From about 1% to about 7% by weight of the catalyst is more preferred.

While TAG can be included in the compositions of the present invention, in a preferred embodiment, the composition is substantially free of TAG. That is, any TAG is present in a very low amount of less than about 0.05% by weight, based on the total weight of the composition as 100% by weight, and preferably about 0% by weight.

Also preferably, the compositions of the present invention comprise a chromophore (also known as a light attenuating compound or moiety or dye). The chromophore can be in the form of a portion of the branched compound (as a functional group on the compound or as part of the polymer backbone or oligomer core), or the chromophore can be physically only mixed into the composition. The chromophore is present in the composition from about 7% to about 75% by weight, and about 11% to about 10% by weight based on the total weight of the polymer and oligomer solids in the composition. About 65% by weight is preferred.

The chromophore is selected according to the wavelength at which the composition is processed. For example, at a wavelength of 193 nm, preferred chromophores include substituted and unsubstituted phenyl (e.g., polyhydroxystyrene), heterocyclic chromophore (e.g., furan ring, thiophene ring) and the foregoing The functional part of the person.

Preferred chromophores at the wavelength of 248 nm include naphthalene (e.g., naphthoic acid methacrylate, 3,7-dihydroxy-2-naphthoic acid), heterocyclic chromophore, carbazole, anthracene (e.g. , 9-fluorene methyl methacrylate, 9-fluorene carboxylic acid) and the aforementioned functional moiety. Another preferred dye for use at 248 nm is an adduct of polyglycidyl methacrylate and 3,7-dihydroxy-2-naphthoic acid. Its formation is described in Embodiment 2, and it has the following structure

Wherein n is from about 4 to about 30.

The present invention also provides significant advantages over the prior art in that no additional crosslinking agent is required and it is preferred to avoid use. That is, the coating composition is preferably a crosslinking agent which is not substantially added. More particularly, the composition comprises less than about 1%, preferably less than about 0.5% and more preferably about 0% by weight, based on the total weight of solids in the composition as 100% by weight.

It will be appreciated that several other optional ingredients may also be included in the composition. Typical optional ingredients include surfactants, amine bases, and adhesion promoters.

Regardless of the specific example, the coating composition is formed by simply dispersing or dissolving the compound (ie, the branched polymer, the branched oligomer, or a mixture thereof) in a suitable solvent system to provide ambient conditions and sufficient It is preferred to form a substantially uniform dispersion for the time. Other ingredients (e.g., PAG) are preferably dispersed or dissolved in the solvent system together with the compound. Alternatively, as in the foregoing, the branched compound can be provided as part of a mother liquor solution, additional ingredients are mixed with the solution, and additional solvent is optionally added to achieve the desired solids content. The branching compound is preferably present in the final coating composition from about 80% to about 99% by weight, and more preferably, based on the total weight of the solids in the composition as 100% by weight. From about 90% to about 99% by weight. The final coating composition preferably has a solids content of from about 0.5% to about 10% by weight, more preferably from about 0.5% to about 6% by weight, still more preferably about 1%, based on the total weight of the composition as 100% by weight. Up to about 4% by weight.

Preferred solvent systems include those previously described in connection with mother liquor formulations. The boiling point of the solvent system is preferably from about 50 to 250 ° C, and more preferably from about 100 to 175 ° C. The solvent system should be used in an amount of from about 90% to about 99.5% by weight, more preferably from about 94% to about 99.5%, still more preferably from about 96% to about 99% by weight, based on the total weight of the composition as 100% by weight. .

Method of using a coating composition

The method of applying the composition to a substrate, such as a microelectronic substrate, simply comprises applying the amount of the composition herein to the surface of the substrate by any known application method, including spin coating. The substrate can be any conventional circuit substrate, and a suitable substrate can be flat or can include undulations (eg, contact or via holes, trenches). Exemplary substrates include tantalum, aluminum, tungsten, tungsten telluride, gallium arsenide, tantalum, niobium, tantalum nitrite, SiGe, a low-k dielectric layer, a dielectric layer (eg, hafnium oxide), and an ion implant layer.

After the desired coverage is achieved, the resulting layer should be heated to a temperature of from about 80 ° C to about 250 ° C, and preferably from about 140 ° C to about 180 ° C, to induce crosslinking of the compound in the layer. Crosslinking will form a further acetal linkage, the final acetal linkage or number of crosslinks being greater (i.e., at least about 1.1 times, and preferably at least 1.2 times) the initial acetal linkage in the branched compound prior to crosslinking. Or the number of links. That is, the crosslinked polymer or oligomer will comprise a linkage having the formula

Wherein R is selected from the group consisting of an aryl group (preferably from about C ₆ to about C ₁₄ ), an alkyl group (preferably from about C ₁ to about C ₈ ), and an aralkyl group (preferably from about C ₆ to about C ₁₂ and about C ₁ , respectively). To about C ₈ ), alkenyl (preferably from about C ₁ to about C ₈ ), cyclic (preferably from about C ₅ to about C ₁₀ ), —CO—, —SO—, —S—, —CONH—, a group consisting of a diol and an adamantyl group.

A particularly preferred R is selected from the group consisting of

The crosslinked layer will be sufficiently crosslinked which will be substantially insoluble in typical photoresist solvents. Thus, the coating of the present invention will have a stripping rate of less than about 5%, preferably less than about 1%, and more preferably about 0% when subjected to a stripping test. The stripping test involves first measuring the thickness of the cured layer (average measured at five different points). This is the average initial film thickness. Thereafter, a solvent (for example, ethyl lactate) is placed on the cured film for about 10 seconds, followed by spin drying at about 2,000-3,500 rpm for about 20-30 seconds to remove the solvent. Using an ellipsometry, the thickness is again measured at five different points on the wafer and the average of these measurements is determined. This is the average final film thickness.

The stripping amount is the difference between the initial and final average film thicknesses. The percentage of stripping is:

The crosslinked film will also have excellent light absorption. At the wavelengths of use (eg, 157 nm, 193 nm, 248 nm, and 365 nm), the cured antireflective layer or coating will have an n value of at least about 1.3, and preferably from about 1.4 to about 2.0. The k value will be at least about 0.01, preferably at least about 0.1, and more preferably from about 0.2 to about 0.8, at the wavelength of use (e.g., 157 nm, 193 nm, 248 nm, 365 nm). The cured layer will have an OD of at least about 4/micron, preferably from about 4 to about 17/micron, and more preferably from about 9 to about 15 microns.

After the layer has been cured, further steps can be carried out as necessary for the particular process. For example, a photoresist is applied to the cured layer followed by exposure to light at an appropriate wavelength followed by post-exposure bake (preferably from about 70 ° C to about 150 ° C, more preferably from about 90 ° C to about 130 ° C). And developing the exposed photoresist to form a pattern. Advantageously, the coating of the invention is also exposed to light as the photoresist is exposed to light. Upon exposure to light, an acid is formed from the PAG and the acid "decrosslinks" the compound in the layer. In addition, this acid also causes the compound to "depolymerize". That is, the acid-catalyzed CO bond (indicated by "*" of at least one (preferably both) of the hemiacetal ester or acetal (which is present in the branched compound and produced during thermal crosslinking) ) The break.

The reaction is as follows:

Wherein R ₁ and R ₂ may be the same or different and include the same variables as described above for R.

The cleavage of these bonds results in the formation of small molecules or moieties that are smaller than the original branched polymer. At least about 80%, preferably at least about 90%, more preferably at least about 95%, still more preferably about 100% by weight of the portion formed by exposure, the individual molecular weights being less than the weight average molecular weight of the starting compound. These parts are easily removed during the development step. That is, the cured composition that has been exposed to light can be removed substantially (and preferably completely) with a conventional aqueous developer such as trimethylammonium hydroxide and KOH developer. Some of these developers are marketed under the names of PD523AD (available from JSR Micro), MF-319 (available from Rohm & Haas, Massachusetts) and NMD3 (available from TOK, Japan). At least about 95%, preferably at least about 99%, and still more preferably 100% of the coating of the present invention will be borrowed, such as tetramethylammonium hydroxide and/or over a period of about 120 seconds after exposure. The alkaline developer of the KOH developer was removed. After exposure, the high percentage solubility in commercially available developers is significantly better than in the prior art where it shortens the process and reduces its cost.

real Example

The following examples are preferred methods in accordance with the present invention. However, it is to be understood that the examples are not intended to limit the scope of the invention.

Example 1

Coating formulation made from branched polymer with strong absorption at 193 nm

In the procedure, 210 mg of terephthalic acid (from Fluka, Milwaukee, WI) was dissolved in 2 ml of propylene glycol monomethyl ether ("PGME" from Harcros, St. Louis, MO) in a 20 ml glass vial. )in. Thereafter, 420 mg of trifunctional vinyl ether (the preparation of which is reported on page 2 of U.S. Patent Application Serial No. 2007/0117049, the disclosure of which is hereby incorporated by reference herein in its entirety) in Milwaukee, WI) is added to the solution. The reaction mixture was stirred overnight at room temperature, then 20 mg of TEA (from Aldrich, Milwaukee, WI) was added to neutralize any residual acid content (and the acid formed during the baking).

Barium triphenyltrifluoromethanesulfonate ("TSP-Tf", available from Aldrich, Milwaukee, WI) was added as PAG in an amount of 5% by weight based on 100 weight of the composition. The reaction mixture was diluted with PGME to a solids content of 2.5% and filtered through a 0.1 micron endpoint filter. The formulation was spin coated onto a ruthenium substrate at 2,000 rpm and then baked at 150 ° C for 60 seconds. The optical constant was measured using a spectral ellipsometer ("VASE", available from JA Woollam Co., Inc.) with an angle change, and the results were as follows: n at 193 nm is 1.379; k at 193 nm It is 0.374.

The film was washed with ethyl lactate ("EL" from Harcros, St. Louis, MO) to test the solvent resistance of the film, and immersed in a photoresist developer (PD523AD) to evaluate dark loss without exposure ( Dark loss). Thereafter, the film was exposed to light derived from a mercury-xenon lamp, followed by post-exposure baking ("PEB") at 130 ° C for 60 seconds and development using PD523AD for 60 seconds. The results are summarized in Table 1 below, which indicates that the material has good solvent resistance and minimal dark loss, but it can be removed by alkaline developer after exposure.

Example 2

Synthesis of PGM/3,7-DNA dye

To make homopolyglycidyl methacrylate (PGM), 37.5 grams of glycidyl methacrylate (Aldrich, Milwaukee, WI) was dissolved in a clean 500 ml three-necked round bottom bottle as a solvent of 161.52 g. Cyclohexanone (available from Harcros, St. Louis, MO). The mixture was stirred at room temperature for 5 minutes until a homogeneous solution was obtained. The dropping funnel and the condenser are connected to the bottle and the entire set of equipment is protected by a stream of nitrogen. The dropping funnel was charged with a solution containing 69.3 g of cyclohexanone (available from Harcros, St. Louis, MO) and 3.65 g of dicumyl peroxide (available from ACROS Organics, NV, NJ). This peroxide solution was added slowly, i.e., to a bottle under a stream of nitrogen and at a temperature of 121 ° C at the beginning of the reaction solution over a period of 1.5 minutes. Once the addition is complete, the reaction mixture is stirred at about 120-126 ° C for 24 hours. 69-70 mg of 4-methoxyphenol (available from Aldrich, Milwaukee, WI) was added as an inhibitor which was added while stirring for dissolution. A sample was taken from the mother liquor for gel permeation chromatography (GPC) analysis, which indicated a _Mw of 13,850. The mother liquor was used in the next step of the reaction without further purification.

100 g of the mother liquor from the foregoing reaction was added to a 500 ml three-necked round bottom flask containing 105 g of cyclohexanone. After the mixture was stirred until homogeneous, 18.63 g of 3,7-dihydroxy-2-naphthoic acid ("3,7-DNA", available from Aldrich, Milwaukee, WI) was added in three portions. Thereafter, 520 mg of benzyltriethylammonium chloride (available from Alfa Aesar, Ward Hill, MA) was added and the reaction mixture was stirred at 115-124 ° C for 24 hours under nitrogen. For this reaction, the polymer _Mw was 28,700. The PGM/3,7-DNA polymeric dye was obtained by precipitating in PGME/deionized water at a weight ratio of 35/65, redissolving in PGME, reprecipitation in hexane, and vacuum drying at 50 °C.

Example 3

Coating formulation containing a branched polymer characterized by an adjustable optical constant of a polymeric dye

The branched polymer backbone was synthesized by the method described in Example 1. In a 20 ml glass vial, 246 mg of cyclopentane tetracarboxylic acid (available from Aldrich, Milwaukee, WI) was dissolved in 2 ml of PGME. Thereafter, 560 mg of the trifunctional vinyl ether as described in Example 1 was added to the solution together with 5 mg of PPTS. The reaction mixture was stirred overnight at room temperature then 20 mg of TEA was added.

Polyhydroxystyrene (available from Hydrite Chemical Company, Brookfield, WI) as a branch of the 193 nm dye was selected and added to the aforementioned reaction mixture. The amount of the dye used was 30% by weight based on the total solids of the reaction mixture. The resulting solution was further diluted with PMGE to a total solids content of 2.5% by weight, and 5% by weight of TPS-Tf was added as PAG based on the total weight of solids in 100% by weight of the formulation. The formulation was spin coated onto a ruthenium substrate at 2,000 rpm and then baked at 150 ° C for 60 seconds. The optical constant was measured using VASE, and the results were as follows: n at 193 nm was 1.524; k at 193 nm was 0.539. The results from the EL stripping, dark loss and exposure/PEB/development tests are summarized in Table 2.

The PGM/3,7-DNA obtained as the 248 nm dye prepared in Example 2 was added to the original branched polymer solution. The dye content varies from 0% to 60% of the total solids content of the formulation, which provides different optical constants. The TPS-Tf as PAG was added in an amount of 5% by weight based on the total weight of the solids of the formulation. The resulting solution was further diluted with PMGE to a total solids content of 2.5% by weight, and the formulation was spin-coated on a ruthenium substrate at 1,500 rpm and thereafter baked at 150 ° C for 60 seconds, after which the EL stripping and dark loss tests were performed. All results are summarized in Table 3. The spin-coated film was exposed to UV light passing through a 248 nm filter for different periods of time. After development at 130 ° C, 60 seconds PEB and using PD523AD, the remaining thickness (in nanometers) was determined and plotted for exposure dose (in millijoules per square centimeter). A representative comparison curve (dye % = 60%) is shown in Figure 1. It was clearly shown that the obtained film was soluble in the photoresist developer due to UV irradiation of 248 nm.

Example 4

Coating formulation of branched polymer absorbed at 248 nm and 193 nm

In the procedure, 204 mg of 3,5-dihydroxy-2-naphthoic acid (available from Aldrich, Milwaukee, WI) was dissolved in 2 ml of PGME in a 20 ml glass vial. Thereafter, 420 mg of the trifunctional vinyl ether used in Example 1 was added to the solution together with 5 mg of PPTS. The reaction mixture was stirred overnight at room temperature, after which 20 mg of TEA was added to neutralize any residual acid content (and any acid that was thermally generated during the baking).

100 mg of "TSP-Tf" was added to the formulation as a PAG. The reaction mixture was diluted to a total solids content of 2.5% by weight by addition of PGME and filtered through a 0.1 micron endpoint filter. The formulation was spin coated onto a ruthenium substrate at 1,500 rpm and thereafter baked at 150 ° C for 60 seconds. The optical constant was measured using VASE, and the results were as follows: n at 193 nm was 1.430, k at 193 nm was 0.246; n at 248 nm was 1.752, and k at 248 nm was 0.275.

The results from the EL stripping, dark loss and exposure/PEB/development tests are summarized in Table 4. The spin-coated film was exposed to UV light passing through a 248 nm filter for different periods of time. After developing at 130 ° C for 60 seconds of PEB and using PD523AD, the remaining thickness (in nanometers) was determined and plotted for exposure dose (in millijoules per square centimeter), as shown in FIG. As a result, it was clearly shown that the obtained film was soluble in the photoresist developer due to 248 nm of UV irradiation, and the contrast was good.

Example 5

Coating formulation for light transmission at 248 nm and 193 nm

In the procedure, a 20 ml glass vial, 123 mg of cyclopentane tetracarboxylic acid (available from Aldrich, Milwaukee, WI) and 172 mg of 1,2-cyclohexanedicarboxylic acid (available from TCI, Tokyo, Japan) were used. Dissolved in 2 ml of PGME, then 316 mg of di(ethylene glycol) divinyl ether (available from Aldrich, Milwaukee, WI) was added together with 10 mg of PPTS. The reaction mixture was stirred overnight at room temperature, after which 20 mg of TEA was added to neutralize any residual acid content (and any acid that was thermally generated during the baking).

TSP-Tf was added as a PAG in an amount of 5% by weight based on the total weight of the solid. The reaction mixture was diluted to 2.5% with PGME and filtered through a 0.1 micron endpoint filter. The formulation was spin coated onto a ruthenium substrate at 1,500 rpm and then baked at 160 ° C for 60 seconds. The optical constant was measured using VASE, and the results were as follows: n at 193 nm was 1.704, k at 193 nm was 0.015; n at 248 nm was 1.587, and k at 248 nm was 0.003. The results from the EL stripping, dark loss and exposure/PEB/development tests are summarized in Table 5.

The film prepared with the coating formulation of the example was exposed to light from a mercury-xenon lamp equipped with a 248 nm filter, imaged in a reticle (contact mode), and then used at 130 ° C for 60 seconds PEB. Tetramethylammonium hydroxide (TMAH) developer rinse. The minimum exposure dose required is less than 20 millijoules per square centimeter. Figure 3 is a photomicrograph of a patterned film.

Example 6

Reaction between tricarboxylic acid and trivinyl butyl ether

In the procedure, 174 mg of aconitic acid (available from Aldrich, Milwaukee, WI) was dissolved in 2 ml of PGME in a 20 ml glass vial equipped with a stir bar. Then, 504 mg of the trifunctional vinyl ether described in Example 1 was added together with 7.5 mg of PPTS. The reaction mixture was stirred overnight at room temperature, after which 30 mg of TEA was added to neutralize any residual acid content (and any acid that was thermally generated during the baking).

"TSP-Tf" was added as PAG in an amount of 5% by weight based on the total weight of the solid content of the formulation. The reaction mixture was diluted to 2.5% with PGME and filtered through a 0.1 micron endpoint filter. The formulation was spin coated onto a ruthenium substrate at 2,000 rpm and then baked at 150 ° C for 60 seconds. The optical constant was measured using VASE, and the results were as follows: n at 193 nm was 1.447, k at 193 nm was 0.246; n at 248 nm was 1.731, and k at 248 nm was 0.024. The results from the EL stripping, dark loss and exposure/PEB/development tests are summarized in Table 6.

Example 7

Reaction between dicarboxylic acid and trivinyl ether

In the procedure, in a 60 ml amber plastic bottle, 258 mg of 1,2-cyclohexanedicarboxylic acid, 420 mg of the trifunctional vinyl ether prepared in Example 1, and 10 mg of PPTS were dissolved in 27.52 g. In PGME, the solid concentration in the formulation was 2.5% by weight. After shaking overnight at room temperature to form a homogeneous solution, TSP-Tf was added in an amount of 5% by weight based on the total solid content. The formulation was spin coated onto a ruthenium substrate at 1,500 rpm and thereafter baked at 150 ° C for 60 seconds. The optical constant was measured using VASE, and the results were as follows: n at 193 nm was 1.446, and k at 193 nm was 0.276. The results from the EL stripping, dark loss and exposure/PEB/development tests are summarized in Table 7 below, which indicates that the material has good solvent resistance and minimal dark loss, but it can be developed by alkali after exposure. Remove the agent.

Example 8

In a 20 ml glass vial, 204 mg of 3,7-dihydroxy-2-naphthoic acid (available from Aldrich, Milwaukee, WI) was dissolved in 2 ml of PGME. Thereafter, 672 mg of the trifunctional vinyl ether described in Example 1 was added to the solution together with 5 mg of PPTS. The reaction mixture was stirred overnight at room temperature, after which 4.38 mg of TEA (0.5% by weight of total solids) was added to neutralize any residual acid content (and any acid that was thermally generated during the baking).

Without further purification, 26.28 mg (3% by weight of total solids) of BBI-109 (from Ciba) was added as PAG, and the reaction mixture was diluted to 2.5% with PGME and filtered through a 0.1 micron endpoint filter. The formulation was spin coated onto a ruthenium substrate at 1,500 rpm and then baked at 160 ° C for 60 seconds. The optical constant was measured using VASE, and the results were as follows: n at 1.48 nm was 1.771, and k at 248 nm was 0.389. Thereafter, M529Y (available from JSR Micro) was applied to the top at 1,750 rpm and baked at 130 ° C for 1 minute. Thereafter, the wafer was exposed to an internal interferometer etching tool set to a 120 nm dense line pattern. After developing at 130 ° C for 60 seconds with PEB and using PD523AD, an SEM image of the wafer cross section was obtained (see Figure 4). Clean bottom anti-reflective coating and top photoresist with no obvious footing or undercut.

Example 9

In the procedure, 210 mg of terephthalic acid (from Aldrich) was dissolved in 3 ml of PGME in a 20 ml glass vial. Thereafter, 672 mg of the trifunctional vinyl ether described in Example 1 was added to the solution together with 10 mg of PPTS. The reaction mixture was stirred at room temperature overnight. Thereafter, 5.6 mg of TEA was added as a quencher, TPS-triflate was added as the PAG, and the mixture was diluted to 2.5% with PGME and filtered through a 0.1 micron endpoint filter.

The formulation was spin coated onto a ruthenium substrate at 1,500 rpm and then baked at 160 ° C for 60 seconds. ARX 3001 photoresist (available from JSR Micro) was applied to the top at 1036 rpm and baked at 110 ° C for 1 minute. Thereafter, the wafer was exposed to an internal interferometer etching tool set to a 150 nm dense line pattern. After development at 110 ° C, 60 seconds PEB and using PD523AD, an SEM image of the wafer cross section was obtained (see Figure 5). Clean bottom anti-reflective coating and top photoresist with no obvious footing or undercut.

1 is a comparative curve of a film formed in Example 3, which uses a formulation containing 60% of a 248-nano dye-filled; FIG. 2 depicts a comparative curve of the film formed in Example 4; FIG. 3 is an example. A photomicrograph of the pattern formed as described in 5; FIG. 4 is a scanning electron microscope (SEM) photograph showing a pattern formed by the composition of Example 8; and FIG. 5 is a pattern formed by the composition of Example 9. SEM photo.

Claims (13)

A method of forming a microelectronic structure, the method comprising: providing a substrate having a surface; applying a composition to the surface, the composition comprising a compound comprising a branched polymer, a branched oligomer, or a mixture thereof, The compound has a first molecular weight and comprises an acid group reactive with vinyl ether, the compound comprising an initial number of linkages having the formula Wherein R is selected from the group consisting of alkyl, alkenyl, aryl, aralkyl, cyclic, -CO-, -SO-, -S-, -CONH-, diol, and adamantyl; The compound in the composition is thermally crosslinked; a photoresist layer is applied to the composition; and the composition is exposed to light and the composition is baked to decrosslink the compound and break the compound into portions, At least about 80% of the individual molecular weights of these moieties are below the first molecular weight. The method of claim 1, further comprising contacting the portion with the developer to remove the portion from the surface. The method of claim 1, wherein the acid group is selected from the group consisting of carboxylic acids, phenols, sulfonamides, fluorinated alcohols, and mixtures thereof. According to the method of claim 1, wherein R is selected from the group consisting of The method of claim 1, wherein the crosslinking results in a composition layer substantially insoluble in the photoresist solvent. The method of claim 1, wherein the crosslinking results in a crosslinked compound comprising a final number of linkages having the formula Wherein R is selected from the group consisting of aryl, alkyl, aralkyl, alkenyl, cyclo, -CO-, -SO-, -S-, -CONH-, diol, and adamantyl, wherein the final number Greater than the initial number. The method of claim 1, wherein the exposing and baking results in a layer substantially soluble in the photoresist developer. The method of claim 1, wherein the exposing and baking breaks at least one bond (*) having a bond of the following formula Wherein R is selected from the group consisting of aryl, alkyl, aralkyl, alkenyl, cyclic, -CO-, -SO-, -S-, -CONH-, diol, and adamantyl. The method of claim 1, wherein the substrate is a microelectronic substrate. The method of claim 9, wherein the substrate is selected from the group consisting of tantalum, aluminum, tungsten, tungsten telluride, gallium arsenide, antimony, bismuth, bismuth nitrite, SiGe, ion implantation layer, low-k dielectric layer, and A group of electrical layers. The method of claim 9, wherein: the substrate further comprises a structure defining a hole, the structure comprising a side wall and a bottom wall; and the applying comprises applying the composition to at least a portion of the side wall and the bottom wall of the hole. The method of claim 9, wherein the substrate comprises an ion implantation layer, and the applying comprises forming the composition layer adjacent to the ion implantation layer. The method of claim 1, wherein the composition is substantially free of a crosslinking agent.